Impact of piflufolastat F-18 PSMA PET imaging on clinical decision-making in prostate cancer across disease states: A retrospective review

Abstract

Introduction: Piflufolastat F-18 (18F-DCFPyL) prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging is approved by the US food and drug administration for initial staging of high-risk prostate cancer, biochemical recurrence (BCR), and restaging of metastatic prostate cancer. Here, we sought to assess how its integration into clinical care may have impacted the management of patients.

Methods: We identified 235 consecutive patients who underwent an 18F-DCFPyL PET scan from August 2021 to June 2022. The median prostate-specific antigen at the time of imaging was 1.8 ng/mL (Range: 0-3740 ng/mL). Descriptive statistics were used to analyze its impact on clinical care for a subset of 157 patients with available treatment information: 22 for initial staging, 109 with BCR, and 26 patients with known metastatic disease.

Results: PSMA-avid lesions were detected in 154/235 (65.5% of) patients. In patients undergoing initial staging, 18/39 (46.2% of) patients had extra-prostatic metastatic lesions; 15/39 (38.5% of) scans were negative and 6/39 (15.4%) had equivocal results. 12/22 (54.5% of) patients had a change in their treatment plan post-PSMA PET scan while 10/22 (45.5%) had no change in their treatment plan. In the BCR cohort, 93/150 (62.0%) had a local recurrence or metastatic lesions. Equivocal and negative scans accounted for 11/150 (7.3%) and 46/150 (30.7%) of scans, respectively. 37/109 (33.9% of) patients had a change in their treatment plan, while treatment was not altered in 72/109 (66.1% of) cases. In patients with metastatic disease, 43/46 (93.5%) had PSMA-avid lesions identified; equivocal and negative scans accounted for 2/46 (4.3%) and 1/46 (2.2%) of scan results, respectively. 6/26 (23.1%) had their tentative treatment plan adjusted after the PSMA PET scan. No change in the treatment plan was observed in 20/26 (76.9% of) cases.

Conclusion: Integration of F-18 PSMA PET imaging impacted clinical decision-making and subsequent management across all stages of prostate cancer. It remains to be seen whether this translates into superior survival outcomes.

Keywords: PSMA PET; biochemical recurrence; decision making; high risk prostate cancer; piflufolastat.